LT1 fuel split
I believe what he is asking is whether or not the Maf ends are causing the large split in fuel trims...which the answer is no. I do agree it makes it more difficult to setup the maf calibration but has nothing to with split fuel trims.
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From: Little Rock, Ar
As I thought I mentioned, when fuel trims are that far off, the splits often narrow when brought more in line. I have seen it many times over the years.
Also inspected that area. No luck.
Update:
I installed my facotory TB on it and the fuel split went from:
B1 +49.9(max on gauage)
B2 -17.x to -24.x
After stock TB:
B1 +49.9
B2 +32.x(cold) +5.x to +15.x(warm)
So I've still got a split, but it isn't a lean/rich split. Just Lean/not as lean lol
Update:
I installed my facotory TB on it and the fuel split went from:
B1 +49.9(max on gauage)
B2 -17.x to -24.x
After stock TB:
B1 +49.9
B2 +32.x(cold) +5.x to +15.x(warm)
So I've still got a split, but it isn't a lean/rich split. Just Lean/not as lean lol
I don't know how many years you have been tuning these full time, but I'm telling you I have seen them narrow dramatically, many times. That needs addressed before worrying about splits.
The time to address splits is after his tuner gets things closer. I have seen splits nearly that bad pretty much go away after getting it closer. Over rich doesn't usually widen fuel trim splits the way very lean does. He still needs to verify the mechanicals are correct. He could also have injector problems. I usually also swap the injectors side-to-side. Have found problems there too.
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From: Little Rock, Ar
Update:
Ohm'd all plug wires. Two had high resistance.
Replaced wires. ALONG with new plugs gapped to .35
Was told to inspect my MAF. It was a bit dirty, so I cleaned it. No change.
I took Ed's recommendation on using Factory metal MAF ends rather than my ported ends.
Installed them, NO change.
So complete run down-
FACTORY MAF
FACTORY THROTTLE BODY
NEW spark plugs gapped .35
NEW header gaskets
Checked for other exhaust leaks--NONE
SWAPPED injector sides
SWAPPED O2 sides
NEW O2's
Inspected O2 EXTENTIONS. LOOKED OK with no burns(will ohm wires if recommended)
Tuner & I played with tune this evening.
Added fuel several times(at one point up to 8% more) and it FIANALLY got B2 where it should be. But adding fuel seem to make the split worse bc B1 was stay at 51%(lean)
B1 WILL NOT COME DOWN.
I am LOST....
Ohm'd all plug wires. Two had high resistance.
Replaced wires. ALONG with new plugs gapped to .35
Was told to inspect my MAF. It was a bit dirty, so I cleaned it. No change.
I took Ed's recommendation on using Factory metal MAF ends rather than my ported ends.
Installed them, NO change.
So complete run down-
FACTORY MAF
FACTORY THROTTLE BODY
NEW spark plugs gapped .35
NEW header gaskets
Checked for other exhaust leaks--NONE
SWAPPED injector sides
SWAPPED O2 sides
NEW O2's
Inspected O2 EXTENTIONS. LOOKED OK with no burns(will ohm wires if recommended)
Tuner & I played with tune this evening.
Added fuel several times(at one point up to 8% more) and it FIANALLY got B2 where it should be. But adding fuel seem to make the split worse bc B1 was stay at 51%(lean)
B1 WILL NOT COME DOWN.
I am LOST....
Last edited by Green3spd; Feb 11, 2013 at 12:02 AM.
Have you swapped sides with the O2 sensors? If that changes nothing, swap sides with the injectors. Do you have an infrared rwhp gun? Shoot the header tubes on the lean side. If you have a cold tube there is a misfire. That will cause high fuel trim numbers on a bank that is not actually lean. Have you looked for black plugs on the high fuel trim side? Have you unplugged an O2 sensor to see if the scan tool shows that side stuck about 450 mv? I don't know how he did it , but I had one guy with O2s hooked the the wrong sides.
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From: Little Rock, Ar
Had a lifter collapse on me(which Comp took care of me on), so I pulled the intake and found a terrible leak at the bottom of the intake runner. So it was pulling air from the oil valley.
Fuel split fixed.
Thx for all the help along the way.
Fuel split fixed.
Thx for all the help along the way.
